Q1 - Yes, total capacity 2.6 Ah
Q2 - try buying 6 packs of these 4.5 Ah
NiMH C Rechargeable Batteries Up To 4500mAh
To charge the pack, try one of these
Ansmann ACS 410P Traveller Battery Pack Charger
I've made my own pack from cells and used an Ansmann charger. Worked a treat and was lots cheaper than buying a manufacturer replacement.
Cheers, Chris